In the automotive industry small diameter tubing is used for the braking system and the ends of the tubes which are connected to the master cylinder and to the brake cylinder are formed at the factory in a predetermined shape for mating with threaded coupling members. The tubes are generally made to a predetermined length to fit the particular vehicles with which they are to be used and if the vehicle is of foreign make the replacement of such a tube in the event that it fails may involve a considerably delay particularly if the failure occurs at a place where the replacement tubes are not available. It is the purpose of this invention to provide a very simple and efficient forming tool which will enable the ordinary garage and/or gas station attendant to replace such a custom made tube with high pressure tubing which is readily availabe but not in any particular length by forming the end or ends of the tube to the required shape on the spot and so eliminate any prolonged delay. Tools for flaring or forming the ends of the tubes are, of course, not new such tubes being shown in the U.S. Pats. to Corrigan, No. 2,117,543, Franck, No. 2,892,480 and Meyer, No. 3,575,033. None of these patents, however, is designed to form the end of a tube as required and, in particular, each of the devices shown in the aforesaid patents is somewhat complicated in construction, requires several operations to perform the forming operation, requires adjustment and substitution of parts during various steps of the forming operation which can be easily lost and which are expensive to manufacture. In contrast, the forming tool of this invention is so simple and inexpensive to manufacture as to be available to every garage and filling station mechanic both because it does not entail any considerable expense to purchase or maintain and does not require a skilled mechanic for its operation.